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the U08 model did not have a constant internal diameter seat tube

it is larger up at the top, i.e. counterbored

this is because a thick shim was employed by the manufacturer which was about 25mm or so in length/height

the OEM saddle pillar was a constant diameter 22.0mm (un stepped)

it may be necessary to ream and go to a larger diameter pillar in order to solve the wobble symptom...

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